Resinous condensation product and manufacture thereof



Patented Oct. 19, 1943 RESINOUS CONDENSATION PRODUCT AND MANUFACTURETHEREOF John F. Olin, Grosse Ile, Mich., assignor to Sharples ChemicalsInc., a corporation of Delaware No Drawing. Application March' 29, 1941,Serial No. 385,857

1'7 Claims. The present invention pertains to a new class of syntheticresins and related condensation products, and to the manufacture of suchnew compositions of matter. The products of the invention are useful asfilm forming constituents of coating compositions, impregnating andstifiening agents for fabrics, molding compositions, adhesives, agentsfor the coating and sizing of paper, and for a wide variety of othertechincal uses. They may be either solid resins or viscous liquidcondensation products which are closely analogous to the solid resins,and they will be referred to hereinafter by the generic term of resinouscondensation products."

Resinous condensation products of the type formed by condensation ofurea with formaldehyde have found wide use in industry, but theircommercial utilization has been limited because of the instability ofthese products and their lack of solubility in water. In many industrialapplications such as those suggested above, a water-soluble resinouscondensation productis desirable. The familiar urea-formaldehydecondensation products are soluble in water only during the initialstages of the condensation reaction. While attempts have been made touse these products in this incomplete state of condensation in cases inwhich a water soluble condensation product is desired, seriousdifiiculties have been encountered in this connection because of theinstability of these initial condensation products. When aqueoussolutions of these products are allowed to stand for a short time, whiteprecipitates or gels are formed, thereby rendering the productpractically useless. Another objection to the use of these partialcondensation products consists in the fact that further condensationtends to proceed after application of the product in a coatingcomposition, for example. These products are obtained in a condensationreaction in which the temperature does not ordinarily exceed 100 C. If acoating film is made of such a product, and heat is applied to set thecoating, the application of this heat results in further condensationand liberation of objectionable formaldehyde fumes.

Objects of the present invention have been to provide a new class ofcondensation products between urea derivatives and formaldehyde and itsequivalents, which is free of the above-noted defects.

' More specifically, an object of the present invention has been toprovide relatively stable water-soluble resinous condensation productsbetween formaldehyde and its equivalents, and urea derivatives.

A further object of the invention consists in cal diethylolurea may beobtained. Similarly, the corresponding propylol-, butylol-, pentylol-,

the application of heat, in cases in which this thermosettingcharacteristic is desired.

A still further object of the invention consists in the desire toproduce resins of this type which may be dissolved in aromatichydrocarbons, alcohols and other organic solvents, in cases in whichsuch solubility characteristics are desired.

Still further objects, and the manner in which the above and thesefurther objects have been attained, will be evident from the followingmore detailed description of the invention.

It is possible, by the technique of the invention described in myco-pending application,

Serial No. 278,175, filed June 9, 1939, now Patent No. 2,253,528, forManufacture of derivatives of urea, to produce compounds having alkylolradicals substituted for one or more of the hydrogen atoms attached tothe nitrogen atoms of urea. Thus, in accordance with Example 3 ofthatapplication, 16.3 mols of ethylolamine and 16.3 mols of urea weremixed in a twonecked flask and agitated during the course of a run bymeans of a mercury sealed stirrer. Heat was applied to the mixture untilthe temperature reached 130 C., and ammonia was discharged from thereaction mixture through a reflux column and ammonia scrubber. Afterapproximately two hours the theoretical quantity of ammonia had beenevolved. Upon cooling, there was left in the flask a crude solution ofbeta-hydroxyethyl urea. The crude product was a viscous, straw-coloredliquid, having a specific gravity at 28 C. of 1.270. A titration showedthat it contained only- 0.22% alkalinity determined as freeethylolamine. consisted principally of the mono-N-beta-hydroxyethyl ureacontaminated with but a small proportion of other constituents and wasof sufficient purity for usein the process of the present invention. Arelatively, pure hydroxyethyl urea crystallizes fromuthe product uponstanding, and this product has a melting point of approximately C. Thispurified product may be substituted for the crude one in the practice ofthepresent invention, 'if desired.

By a procedure analogous to that described above, the variousalkylolureas may be produced, by a proper choice of the alkylolamine tobe condensed with urea and of the proportion of alkylolamine to urea.Thus, by condensing diethylolamine with urea, unsymmetricaldiethylolurea may be obtained, and by condensing two mols ofethylolamine with urea, symmetrihexylol-, eta, ureas may be obtained bychoice of the appropriate alkylolamine' for condensation with urea andproper regulation of propor- This product a tions to efiectsubstitution. of one or more alkylol radicals for the hydrogen atoms ofthe urea molecule, as desired.

In the condensation of alkylolamines with urea as described above, anumber of compounds are produced in addition to the alkylolureas. Thus,a mixture containing products A to E of the following equations may beproduced by condensing a dialkylolamine with urea, by reaction of thehydrogen and/or alkylol groups of the amines with urea. The relativeproportions of these products are dependent upon the proportions of thereactants, as indicated by the equations.

FROM DrALKYLoLaMmEs NH: NH: HN(ROH)1 4*- 3:0 NE;-

NH: M3011 (a) rim micron a+=o HNCROH);

When a mono-alkylolamine is condensed with urea, the resulting mixturemay also include a variety of urea derivatives, as follows (Compounds F,G and H, below) The present invention rests upon the discovery that avaluable and new class of resinous condensation products may be obtainedby condensation of formaldehyde or its equivalents with urea derivativesobtained by condensation of urea with monoand di-alkylolamines. In thepreferred practice of the invention, alkylolamines having between twoand six carbon atoms are employed in producing the urea derivatives tobe condensed with formaldehyde. These urea derivatives may be condensedwith formaldehyde or other methylene containing body in the same manneras that familiar to those skilled in the art in the preparation of thefamiliar ureaformaldehyde resins. Thus, when the crude reaction mixturesor purified hydroxyalkylureas discussed above, are condensed withformaldehyde with or without an acid, basic or neutral catalyst, resins.having very valuable technical characteristics, as discussed above, areobtained. In the practice of this condensation, the reaction mixture ispreferably heated to speed up the reaction. These resins have thevaluable watersolubility characteristics discussed above in connectionwith the initial condensation products of simple urea and formaldehyde,but theydo not have the serious drawback of instability of thesepreviously known resinous condensation products.

A further advantage of the resinous condensation products of the presentinvention, in addition to their stability, consists in the fact thatthey may be made to have thermosetting or thermoplastic characteristics,depending upon the use to which the condensation product is to be put,by observance of appropriate conditions. By mixing the urea derivativeswith a relatively small proportion of simple urea, biruet or melamine,and condensing the resulting mixture with formaldehyde, a solidthermoplastic resin may be obtained, which is harder than the productobtainable when the simple urea is omitted. When beta-hydroxyethylorother hydroxyalkylurea, for example, is condensed with formaldehyde inthe presence of at least 10% of urea by heating to a temperature of 1400., a resinous condensation product is obtained which sets to form ahard solid coating upon cooling. In this connection, it should beobserved that a similar result can be attained by combining a smallamount of the preliminary condensation product of urea and formaldehydewith the partially condensed product from the urea derivative andformaldehyde, and completing the condensation of these products byheating the two partial con-- densation products together. If a viscousliquid condensation product is desired, on the other hand, the ureaderivative may be combined with an alkyl urea to produce a resinouscondensation product having more fluid characteristics than would beobtainable if the alkyl urea were omitted.

The modifications of procedure for causing these resins to assumevarious physical forms are relatively simple. For example, the watersoluble thermoplastic type is obtained in cases .where the ureaderivative and simple urea, in

quantity not sufficient to cause gellation, are reacted withformaldehyde in the presence of volatile organic acid catalysts.Thermosetting resins may be obtained simply by the addition of anonvolatile acid to the resins just described, or to the urea derivativeprior to condensing it with formaldehyde. In order to obtainthermosetting resins, however, at least a small amount of simple ureashould be present. The organic solvent-soluble resins are produced byconducting the initial and/or final resinification in the presence ofhydroxyl containing substances such as butanol.

Valuable resins having the property of solubility in aromatichydrocarbons, alcohols and other organic solvents may be obtained in thepractice of the invention by conducting the condensation reactionsbetween the methylene-containing body and the urea derivative in thepresence of a suitable organic solvent, such as an alcohol. Thus, whenbutyl alcohol is added to the mixture of alkylol urea with formaldehyde,for example, either before the heating is commenced, or after themixture has been heated for a time to efiect preliminary condensation,the final product of the reaction will be a resinous condensationproduct which is soluble in various organic media, and can thus beconveniently applied as a protective coating or plasticizer in lacquers,varnishes and other coating compositions. It may also be used as aplasticizer for molding compounds.

While the condensation products of the present invention may be producedby heating the reactants in the presence of an acid, basic or neutralcatalyst, or indeed without any catalyst at all, best results in thepractice of the invention have been obtained by the use of organic acidsas catalysts, formic, and acetic acids being preferred. In case athermosetting resin is desired, lactic acid may be used as the catalyst.In this connection the desired thermosetting characteristic may beattained by substituting lactic acid for the lower molecular weight acidin the condensation reaction, or by conducting the condensation reactionwith the aid of the lower acid, and adding the lactic acid to thesolution of the condensation product forming the coating composition inorder to convert this product to the thermosetting form upon baking.

The\following examples illustrate the process and products of theinvention:

EXAMPLE I 240 parts of N -beta-hydroxethylurea, 240 parts of 37% aqueousformaldehyde solution and 15 parts of a 93% solution of acetic acid wereplaced in a vessel equipped with an agitator and heated to 130 C. untilsubstantially all of the water was removed. The resultingresinous'condensation product was a viscous liquid at the temperature of130 0., but solidified upon cooling, and was found to have a meltingpoint of 46 C. by the ring and ball method. This resinous condensationproduct was thermoplastic, unusually stable, water-white, and soluble inwater. It was found to be compatible with other water soluble adhesiveingredients such as methyl cellulose, poly-vinyl alcohol, casein, etc.It was dissolved in distilled water to produce a liquid prodnet of thedesired consistency. The resulting aqueous solution was relatively freeof formaldehyde odor, was water-white, and possessed excellent adhesiveproperties. When it was formed into a film and baked for one hour at 250F. with lactic acid present as a catalyst, it was found not to undergofurther condensation and it remained tacky and plastic.

EXAMPLE II 240 parts of N-beta-hydroxyethylurea, 24 parts of urea and240 parts of 37% aqueous formaldeas a catalyst was'baked for one hour at250 F. and was found 'to form a thermosetting, water and alcoholresistant film, which was tough and elastic.

EXAMPLE III 240 parts of N-beta-hydroxyethylurea, 24 parts of urea and240 parts of 37% aqueous formaldehyde solution were heated until thetemperature reached 100 C. 10 parts of concentrated hydrochloric acidwere then added. The partially condensed resin gelled immediately. Thisgel was dried in an oven overnight at a temperature of 125 F. and thencomminuted and molded at 95 C. under 5000 lbs. pressure for 30 minutes.The button resulting from this molding operation was a clear,glass-like, tough and elastic product, and was found to be stronglyresistant to attack by organic solvents and water.

EXAMPLE IV 35 parts of unsymmetrical diethylolurea (ob-.

to produce a thermosetting film when baked for one hour with a smallquantity of phosphoric acid at a temperature of 250 F., to yield a hard,tough, elastic, film.

EXAMPLE V 50 parts of N-isobutylolurca, 50 parts of 37% aqueousformaldehyde solution and 7 parts of 93% acetic acid were heated withagitation until the temperature reached 150 C. The resultingcondensation product was found to be a watersoluble, water-whitethermoplastic substance, and was stable in aqueous solutions. Filmsformed fromsuch solutions, when baked for one hour at 250 F., were foundto be thermoplastic.

EXAMPLE VI 30 parts of N-isobutylolurea, 113 parts of 37% aqueousformaldehyde solution, 15 parts of urea and 4 parts of 93% acetic acidwere placed in an open vessel equipped with an agitator and processed ina manner similar to the reactants of Example V, except that the,polymerization was 7 carried on at a temperature of 135 C. instead of150 C. The resulting resinous condensation product was found to have amelting point of 50 C. and was soluble in water. Aqueous solutions werestable, and water-white, and they were relatively free from formaldehydeodor.

EXAMPLE VII 37.5 parts of N-isobutylolurea, 101 parts of 37% aqueousformaldehyde solution, 12.5 parts of urea and 5 parts of 93% acetic acidwere charged into a vessel equipped with a distillation take-01f and anagitator. The resulting mixture was heated to a temperature of 0., waterbeing removed during the heating operation. To the resulting hotresinous solution, 50 cc. of butyl alcohol were added slowly duringcontinued stirring of the mixture. The resulting mixture was refluxed atboiling temperatures (117-125 C.)

tions. It is a water-white and stable resin, and is compatible withalkyd and other resins and with nitro-cellulose solutions. Films formedfrom solution of these resins by addition of non-volatile acid may becaused to be thermosetting,

tough and elastic. They are resistant to solvents and are not readilysoftened by water after being baked for one hour at 250 F.

EXAMPLE VIII 90 parts by weight of monoethylolurea, 100 parts 37%formaldehyde, 100 parts of methanol and 4 parts of 95% acetic acid werecharged into a 1000 cc. beaker and heated to 50 C. parts of melaminewere then introduced over a period of five minutes and the heatingcontinued until the temperature reached 110 C. The resin was nowdissolved in equal weight of water to yield a clear, water-whitesolution. Films formed from this solution of resin are characterized,after baking for 30 minutes at 125 C., by their toughness andconsiderable hardness.

It will be readily understood by those skilled in the art that the aboveexamples represent but ,a few of the many possibilities of applicationof the principles of the invention. As pointed out above and in myco-pending application Serial No. 380,669, filed February 26, 1941, thereaction between alkylolamines and urea or-certain urea derivatives is ageneral one, and may be applied in their manufacture by the use ofalkylolamines, such as ethylolamine, diethylolamine, triethylolamine,propylolamines, butylolamines, etc. Alkyl-alkylolamines such as alkylaminoethanols, alkyl diethylolamines, and dialkyl aminoethanols maylikewise be condensed with urea, as may also amino alkanediols and-triols, such asl-amino- 2,3-propanediol. Diamino alkanols such as 1,3-di-amino-2-propanol may also be condensed with urea in the generalmanner indicated by the above equations. All of these various reactionproducts resulting from condensation of the amino compounds with ureamay in turn be condensed with formaldehyde to produce resins or relatedcondensation products. The following example illustrates the manufactureof a resin from 2-ethyl-2-ureido-1,3-propanediol, this compound beingobtained by condensation with urea of 1,3,dihydroxy, 2-ethyl, 2-aminopropane, and having the following formula:

OH H-JF-H OH urea the product was found to gel.

an open vessel equipped with an agitator until the water was driven off(150 C.) At this temperature the resinous condensation product was aviscous liquid. Upon being dissolved in an equal weight of distilledwater the solution was found to be water-white, stable, film-forming andthermo-plastic.

The following example illustrates the manufacture of a resinouscondensation product from the condensation product between 1,3-diaminopropanol and urea.

EXAMPLE X grams (one mol) of pure 1,3-diaminopropanol and grams (2 mols)of urea were placed in a 1 liter flask fitted with a thermometer,mercury sealed stirrer and reflux condenser, with a water scrubberattached to the end of the reflux condenser. A small amount of aceticacid catalyst was added. Upon heating the mixture, with stirring, it wasobserved that complete solution occurred at a temperature of about 100C. and rapid evolution of ammonia occurred above C. The reaction, asjudged by the evolution of 32 grams of ammonia, was complete in hour at-150 C. The reaction mass was poured into a tin plate while hot. Uponcooling it presented itself as'a very pale colored resinous material,which was slightly tacky to the touch. This material was easily solublein water and was believed to consist essentially of 1,3-diureido2-propanol. Upon being condensed with formaldehyde and 10% simple Thegel appeared to possess rather unusual properties in that it could beeasily broken in the fingers. A quantity of this gel was pulverized anddried at a temperature of 80 C. overnight. The resulting powder wasmolded at 5000 lbs. pressure at 125 C. The resulting button wastransparent and extremely hard.

Still further modifications will be obvious to those skilled in the artand I do not therefore wish to be limited except by the scope of thefollowing claims.

The term alkylolureas as used in this specification and claims isintended to cover only those compounds formed by substituting for one ormore hydrogen atoms of the urea molecule, an alkylol group. The term isnot intended to cover such compounds as carbamylalkylureas orcarbamylalklamines. Such compounds may be formed incidentally in theformation of alkylolureas and may be present when the resinificationaction takes place, but the reaction upon which this application isbased is essentially between the alkylolureas defined above andformaldehydes.

I claim:

1. As a new composition of matter, the resinous condensation productobtained by condensing an alkylolurea containing at least two carbonatoms in an alkylol radical with formaldehyde.

2. As a new composition of matter, the resinous condensation productobtained by condensing an alkylolurea containing a single alkylolradical having at least two carbon atoms with formaldehyde.

3. As a new composition of matter, the resinous condensation productobtained by condensing an alkylolurea containing two separate alkylolradicals of which each alkylol radical contains at least two carbonatoms with formaldehyde.

4. As ,a new composition of matter, the resinous condensation productobtained by condensing an alkylolurea containing between two and sixcarbon atoms in an alkylol radical with formaldehyde.

5. As a. new composition of matter, the resinous condensation productobtained by condensing a mixture containing an alkylolurea containing atleast two carbon atoms in an alkylol radical and a compound chosen fromthe class consisting of urea and biuret, with formaldehyde.

6. As a new composition of matter, the resinous condensation productobtained by condensing an alkylolurea containing at least two carbonatoms in an alkylol radical and unsubstituted urea with formaldehyde.

7. As a new composition of matter, the resinous condensation productobtained by condensing beta-hydroxyethylurea with formaldehyde.

8. As a new composition of matter, the resinous condensation productobtained by condensing an alkylolurea containing at least two carbonatoms in an alkylol radical with formaldehyde with the aid of an organicacid catalyst.

9. In the manufacture of resinous condensation products, the processcomprising condensing an alkylolurea containing at least two carbonatoms in an alkylol radical with formaldehyde.

10. In the manufacture of resinous condensation products, the processcomprising condensing an alkylolurea containing between 2 and 6 carbonatoms in an alkylol radical with formaldehyde.

11. In the manufacture of resinous condensation products, the processcomprising condensing an alkylolurea containing at least two carbonatoms in an alkylol radical with unsubstituted urea and withformaldehyde,

12. In the manufacture of resinous condensation products, the processcomprising condensing a mixture of an alkylolurea containing between 2and 6 carbon atoms in an alkylol radical and a compound chosen from theclass consisting of urea and biuret with formaldehyde.

13. In the manufacture of resinous condensation products, the processcomprising condensing an alkylolurea containing at least two carbonatoms in an alkylol radical with formaldehyde in the presence of analcohol.

14. As a new composition of matter, the resinous condensation productobtained by condensing with formaldehyde a condensation product whichhas been obtained by condensing with urea an alkylol amine having atleast two carbon atoms in an alkylol radical and having at least onehydrogen atom attached directly to the nitrogen atom.

15. In the manufacture of resinous condensation products, the processcomprising condensing a mixture containing an alkylolurea having atleast two carbon atoms in an alkylol radical and a compound chosen fromthe class consist ing of urea and biruret with formaldehyde, in thepresence of an alcohol.

16. A composition as defined by claim 14 in which the amine is amono-alkylol amine.

17. A composition as defined by claim 14 in which the amine is adi-alkylol amine.

JOHN F. 'OLIN.

